Alcohols are important commodity feedstocks for a variety of industrial products, and ethanol, for example, is used as a fuel additive to gasoline. Further, ethanol can readily be dehydrated to ethylene, which in turn may be converted, for example, to useful polymer products. Processes exist to produce ethanol from the hydrogenation of acetic acid. In one such process, ethanol may be formed from an interaction of acetic acid with a ruthenium catalyst at pressures of about 70 MPa to about 95 MPa. Under such conditions, the yield of ethanol may be about 88%. At lower pressures of about 20 MPa, only about 40% yield of ethanol was obtained.
Another process was described for producing ethanol by hydrogenating acetic acid in the presence of a cobalt catalyst. The process may require pressures of about 4 MPa to about 12 MPa, although pressures of about 30 MPa may be required to improve ethanol percent yield. Further, the catalyst may require additional components such as copper, manganese, molybdenum, chromium, and phosphoric acid.
Both of these processes require expensive catalysts and high pressures for reasonable percent yields of ethanol. There is thus a need for a process that uses a cost-effective catalyst and can occur under reasonable conditions.